Improvement in air-heating furnaces



2 sh t--sh' 1. J. M. THATCHER. ees eet v Hot-Air.-..Furnace.

No. 71,244. Patented Nov. '19, 1867.

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UNITED STATES PATENT OFFICE.

JOHN M. THATGHER, OF BERGEN, NEW JERSEY.

IMPROVEMENT IN AIR-HEATING FURNACES.

Specification forming part of Letters Patent No. 7 1,244, dated November 19, 1867.

To all whom it may concern:

Be it known that I, JOHN M. THA'rcHEn, of Bergen, Hudson county, New Jersey, have invented certain new and useful Improvements in Air-Heating Furnaces; and do hereby declare that the following is a full and correct description thereof, reference being had to the annexed drawings, making a part of this specification, and to the letters of reference thereon.

Figure 1 represents a longitudinal section of a furnace with my improvements; Fig. 2, a front elevation; Fig. 3, a horizontal crosssection through red line y y, Fig.1; Fig. 4, section of sliding plate bearer for grate; Fig.

, cross-section through red lines .r x, Fig. l;

Fig. 6, rear elevation of furnace, showing draft-dues and inner wall in dotted lines; Fig.

7, a broken plan view of the corrugated bottom plate of the flue-passage, with air-tubes, looking up from below; Fig. 8, plan view of the furnace with walls and covering broken away.

My said invention consists of several i-mprovements in hot-air furnaces designed to be set in brick-work, or inclosed in any suitable manner; and consists, first, in combining with the dre-pot a central feeding-funnel, contracted at a point a short distance above the place of discharge, and enlarging again above the point of greatest contraction, being in the form of two hollow frustums of cones united together by their smallest ends. The contraction of the upper part prevents the coals from feeding down too fast, and pressing upon the coals in that part of the feeder below, and the enlargement of the lower end permits a free discharge, which is of great advantage in the feeding of soft coals, which are liable to swell and clog the feeder by reason of the heat of the fire.

My invention also consists in thecombination and arrangement of a passage-way from and through the furnace front to and into the ire-pot at the bottom thereof, the passage-way being of sufficient width and height to admit of the introduction of a slicer or poker for the purpose of slicing the fire and removing the clinker from the grate-bars forward, the bottom of the passage-way being on a line with the top surface of the grate-bars, and the top and sides of the passage-way being formed by an inclosing-plate extending from the tire-pot to the furnace front, and joining at the sides the ashpit box, so as to prevent any communication between said passage-way leading from the furnace front into the lire-pot and the hot-air chamber surrounding the fire-pot; and this partof my invention further consists in combining, with said inclosed passage from the furnace front to the fire-pot a downward opening between the furnace front and lirepot leading from said inclosed passage to the ash-pit, whereby clinkers and other matter removed from` the lire-pot may fall into the ash-pit; and this part of my invention also consists in combining, with the ash-pit, a sifting-drawer, having perforations in the bottom when such drawer extends in front of the grate and .under the downward passage from the clinker-opening.

My invention also consists in a com binatiou of a sliding dead-plate and grate-bearer with the grate, ash-pit, and the downward passage leading' to the ash-pit, said sliding dead-plate extending across the ash-pit, and having its edge next to the grate curved correspondingly to the curve of the grate, so as to support the grate as a bearer, permitting the grate to he oscillated horizontally, for the purpose of shaking out the ashes, and, when moved on its slides away from the grate, permitting the grate to be tipped to discharge its contents into the ash-pit.

My invention also consists in the combination of the corrugated bottom plate ofthe fluepassage from the fire-pot to the chimney with the air-heating tubes which pass through said p passage, which tubes are arranged in rows and i; i joined to the corrugated plate upon the ridges or V-parts of said plate, which project up into the iiuepassage,whereby the ashes or other solid matter coming from the re-pot is prevented from accumulating between the tubes of each row and forced to accumulate inthe grooves or depressed portion of the corrugated bottom plate between the several rows of tubes, thus affording facility for cleaning the bottom plate by means of a V-scraper introduced/from the rear of the furnace, and at the same time, by keeping a large portion of the corrugated bottom plate free from dust and ashes, largely increasing the air-heating surface of the fur nace; and this part of my inventionsfurther consists in combining with the said flue-pas? sage,conta1ning the vertical air-heatingl tubes,

stopper is provided to close this manhole or' cleaning-out passage when the furnace is in operation. l

My invention further consists in increasing the depth of the fluefpassage containing the vertical air-heating tubes and the length of said tubes relatively to each other in proportion to their'distance from the fire-pot, so that a larger air-heating surface is obtained to coin'- pensate fonthe diminished heat acting upon the tubes at a distance from the tire-pot.

My invention also consists in connecting the flue-passage containing the vertical airheating tube with a main tlue or pipe leading to the chimney, by means of two flues or pipes, which form a fork-connection with said main flue, a-nd are connected to the luepassage containing the vertical air-heating tubes. on opposite sides ot' said flue, near the bottom thereof, thereby compelling the products of combustion from the furnace to circulate at' the sides as well as through the middle of the line-passage containing the vertical air-heat ing tubes.

The drawings illustrate a furnace for brickwork in, which my inventions are embodied. The fire-pot c is a cylindrical casting such as commonly used for that purpose, and sits upon a box, also of east-iron, which incloses the ash-pit b. The surrounding outer wall c and inner wall d are shown (broken off) in the drawings. The fire-pot is placed at sufcient distance from the furnace front e to allow the hot'air chamber inclosed in the inner surrounding walls to extend around the fire-pot, between it and the furnace front. Au annular box, f, is placed upon the upper part of the tire-pot, extending around the same, and is provided with perfor-ations to admit air from the hot-air chamber into it, and is also connected by hollow arms to an interior smaller annular box, which is suspended by said arms in the upper part ofthe tire-pot, in the middle of the same, said interior annularbox being also perforated with holes to permit air supplied to it from the outer annular box to pass into the ire-pot and mingle with the products of combustion. The 'centerieeding-funnel g rests upon this interior annular box, and is contracted a short distance above the` place of discharge, enlarging above the point of greatest contraction, being of the form of two hollow frustums of cones joined together at their smallest ends, the lower iiaring part being just over the fire, and the upper part flaring upward until it joins a conduit, g', which may be bent solas to open lthrough the front wall of the furnace, and which supplies the l fuel to the feeding-funnel g', directly over the fire. y

It is not essential to this part of my invention that the feeding-funnel shall be supported by the hollow annular air-heating boxes which supply air to the products of combustion in the re-pot, although l consider it a forni of construction which is most desirable. If, however, the air-heating annular boxes are dispensed with, the feeding-funnel may be supported from the top of the furnace 'hy'its connection with the conduit g', or by radial arms from the sides of the lire-pot, or in any other suitable manner. A feeding-door, h, connected by jams h to the furnace front and furnace, opens into the upper part of the furnace above the tire-pot, as usual in furnaces. At the bottom of the fire-pot, in the front part thereof, is a clinkercleaning aperture, fi', which extends forward to and through the furnace front, the passageway being inclosed by the plate i', so that it shall not have any communication with the surrounding hot-air chamber e. A stopper may be used to close this clinker-cleaning passage, or that part of it which leads into the fire-pot, if desired, or it may be left open to supply air to the fuel in the fire-pot. rlhe aperture should be of sucient width and height to permit the introduction and use of a slicer, or a poker, or other suitable instrument for the purpose of slicing the fire, cleaning the grate-bars from clinker, and removing 'the clinker which may be drawn out through this passage into the room in front of the furnace front, if desired, when'the downward passage j is not used, in which casethere should be a plate across the space between the ire-potand furnace front, on a level with the top surface of the grate-bar. The downward )assa-O'e between the furnace front and rratef'` 1 c .7

is an opening leading from the clinkerlcleaning passage down to the ash-pit, for the purpose of allowing the clinker and ashes to fall Vfrom the clinker-cleaner opening'into the ash-pit. Below the grate-bars, and extending across the ash-pit forward of them under the clinker-cleaner opening1 is an asli`sifting I drawer, 7c, provided with a hinged front, 7c', and

having a perforated bottom. rlhis drawer slides in and out of the ash-pit, through the furnace front, on suitable slides dat the sides of the ash-pit. The grate m, which is of circular form, is supported upon a rocking1 bearer, m1, and connected therewith by a center pivot, m2, so as to havean oscillating motion in two directions-one horizontal, for shaking out the ashes, and the other vertical, to discharge the contents of the tire-pot by tipping the front part of the grate downward, the grate being prevented from tipping upward by reason of the rim extending beyond the line of the front part of the lire-pot. The grate is supported in front by the sliding bearer a, which extends across the ashpit and slides in suitable slides al nl on each side thereof. The sliding bea-rer means of a V-scraper.

n is curved at that part on which-the grate rests, to coliform to the curve of the rim ot the grate, as clearly shown in the drawings. On the under side ofthe sliding plate, infront thereof, is a lip, n2,'for convenience in taking hold of the plate to draw it forward when it is desired to remove it in order to tip the grate. Above the `tire-pot is a'series of airheating tubes, o, disposedin a circular form,.

which pass through andare Supported by an inclined circular plate, o', which joins the top of the tire-pot. The products of combustion pass from the fire-pot into the upper part of the furnace, and from thence into a horizontal flue-passage, p, which contains a series of rows of vertical air-heating, tubes, 19 p', which, passing through said fine-passage and the upper and lower plates thereof', are secured at their ends in said upper and lower plates. The lower` plate q of said horizontal flue-passage is corrugated, the corrugations q being of a V form, and there being a corrugation for every row of air-heating tubes, the air-heatin g tubes being placed upon the ridges, or that part of the corrugation which projects upward into the flue-passage, so that the ashes or the solid matter coming from the tire-pot cannot remain upon the corrugated part between the tubes constituting arow, but is compelled, by thelnclined sides of the corrugations, to fall into the depressed portion of the corrugated surface of the bottom plate, which comes between the rows of tubes, whence it can .readily be removed through the rear man-hole by At the rear of the horizontal flue-passage p is a cleaning-out passage-way or man-hole, r, which passes through the two surrounding rear walls and connects with the liuc-passage at the bottom thereof. This passage-way is of the width ot' the flue-passage p, and of sufficient height to introduce a V-scraper or other proper instrument for the purpose of scraping out the ashes from the depressed portions of the corrugated bottom plate.

The man-hole is closed, when not used for cleaning out the tine-passage, by a door or stopper, lr', from the outside of the rear wall. The use of this man-hole obviates the necessity ot taking down portions of the surrounding walls, and taking apart the plates which form the fine-passage p, to clean out the same.

The due-passage increasesin depth as it recedes from the lire-pot, and the air-heating tubes correspondingly increase in length, for the purpose of giving a greater air-heating surface to the tubes farthest from the fire than those tubes nearer to the tire. The flue-passage p being of considerable width, the products of combustion would tend to pass through the middle thereof, rather than to be distributed equally throughout the interior, so as to act upon the air-heating tubes at or near the sides ofthe flue-passage, the same as upon those in the middle. Therefore, I have connected said flue-passage with the pipe leading to the chimney by means of two flue-passages, s s', which connect with the flue-passage p by nleans'ot' the man-hole passage nr'near the sides of the said passage, and, rising in an inclined direction, unitev to the pipe t, leading to the chimney, by a forked connection, u, or in any suitable manner. vThe two tlues s s should each be of half the capacity of the required tluepassage from the flue-passage p to the chimney, so that the products of combustion coming from the fire-pot shall .be drawn toward the sides of the flue-passage p as they pass through the same, in order to distribute the heat equably upon the Vertical air-heating tubes.

What I claim as my invention and improvement in hot-air furnaces is as follows:

l. In `combination with the fire-pot a central feeding-funnel, in the form of two hollow frustums of cones, united together at their -and downward passage leading from the clinker-cleaning passage-way, Athe sifting-drawer, having a perforated bottom extending. forward of the grate-bars and across underneath said downward passage, substantially as described.

5. The sliding dead plate or front bearer to the grate, in combination with the grate and downward passage, substantially as described.

6. The combination of the corrugated bottom plate of the flue-passage from the tire-pot to the chimney with the air-heating tubes, which pass through said passage, which tubes are arranged in rows and joined to the corrugated plate upon the ridges or V parts of said plate, which project up into the flue-passage, whereby the ashes or other solid matter coming from the tire-pot is prevented from accumulating between the tubes of each row, and forced to accumulate in the grooves or depressed portion ofthe corrugated bottom plate between the several rows of tubes, thus ai'ord- Ving facility for cleaning the bottom plate and creasing in depth with airheating tubes increasing in length in proportion to their distance from the lire-pot, whereby greater tubular air-heating surface is obtained to compensate for diminished hea-t, substantially as described.

9. In combination with the Hue-passage and vertical air-heating tubes the two connectingfines, which connect said nue-passage with the mainline leading from the chimney, said two ues connecting with the Hue-passage ou opposite sides and near thev bottom thereof, substantially as described.

JOHN M. THATCHER. Witnesses:

F. C. CDRFADWELL,` Jr., J oHN J. BARNETT. 

